Bash misc tips
A nice thing to do is to add on the first line
This will produce some interesting output information
Reading user input with read
In many ocations you may want to prompt the user for some input, and there are several ways to achive this. This is one of those ways:
#!/bin/bash echo Please, enter your name read NAME echo "Hi $NAME!"
As a variant, you can get multiple values with read, this example may clarify this.
#!/bin/bash echo Please, enter your firstname and lastname read FN LN echo "Hi! $LN, $FN !"
Getting the return value of a program
In bash, the return value of a program is stored in a special variable called $?.
This illustrates how to capture the return value of a program, I assume that the directory dada does not exist. (This was also suggested by mike)
#!/bin/bash cd /dada &> /dev/null echo rv: $? cd $(pwd) &> /dev/null echo rv: $?
Capturing a commands output
This little scripts show all tables from all databases (assuming you got MySQL installed). Also, consider changing the ‘mysql’ command to use a valid username and password.
#!/bin/bash DBS=`mysql -uroot -e"show databases"` for b in $DBS ; do mysql -uroot -e"show tables from $b" done